Paint and method of making same.



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l 'rnou or u a w u traumas-Q To whom it may coace Be it known that l, hnnunnion Srn,

Jr, a citizen of the United States, residing at Uakmont, Allegheny count Pennsylvania, have invented a new an useful improvement in Paints and Methods of Make mg the Same, of which the following is a full, clear, and e xact description.

My invention" relates to paints, and more particularly to those designed for covering and protecting iron and steel and other metals from corrosion, such as in structural iron work exposed to dampness, acid fumes, etc.

- l have discovered that if melted coal tar pitch is mixed with solvent naphtha at a somewhat high temperature; a. a, prefer-- ahly between 100 degrees and 200 degrees,

centigrade, ll can thereby ohtain a colloidal solution which affords a cod paint; of par-- ticular value for protectmg iron and steel from corrosion.

T prefer to use ordinary solvent naphtha direct without any purification heyond its production by simple distillation, as the suhstances contained in ordinary solvent naphtha facilitate the holding of the pitch in solution. Solvent naphtha which has been purified hy sulfuric acid is not as effective for this purpose. Solvent naphtha does not form a solvent for cold coal tar pitch for this purpose, and my improved paint is n t a real solution, but a colloidal solution. is is shown by the fact that if the solvent naphtha is used in excess of a certain percentage the finely divided pitch will hegin' to precipitate. Such precipitation will hegin if the proportion of solvent naphtha till exceeds ahout fifty per cent. by volume of the mixture.

The solvent naphtha which I use may he defined as the liquid fraction obtained from lli llll

coal tar or from the light oils recovered from coal gas or other illuminating gases, hut distilling ahove 120 degrees centigrade. Pref erahly ninety per cent. of such solvent naphtha should distil under 210 degrees centigrade. i

w boiling point henzols may be mixed with this solvent naphtha, in small proportions, hut their use is not an advantage and may injure the quality of the paint by precipitating the free carloon.

ft is desirable that the coal tar pitch should have as low a content of freecarbo'n ecfficatlon of Letters Patent. Patpyytp Arm, t3, ft;

, 1. a application edl uary 1t, tart. serial no. on

as possible. It isprefe'rahly made from loyproduct coke oven tar, of which the original percentage of freecarhon should be not over six per cent; and it is desirable to use a medium soft grade of this pitch, although harder pitches may be satisfactorily used. By coal tar pitch 7 I mean the ordinary commercial coal tar pitch which is a residue from the modern distillation of coal tar up vention lies in the colloidal solution of coal tar pitch insolvent naphtha, the pitch being preferably made from tar low in free carloon. Other ingredients may he added to the paint, if desired, and other changes may be made without departing from my invention.

1 claim:

l. he a new composition of matter, a paint having as its essential 'constituent a f colloidal solution of coal tar pitch in solvent fill naphtha,'and which will readily dry to form a smooth glossy surface.

2.. As a new composition of matter, a paint having as its essential constituent a colloidal solution of coal tar pitch in solvent naphtha, and which will readily dry to form a smooth glossy surface, the coal tar pitch having a relatively low content of free carloonl 3. As a new composition of matter, a paint having as its essential constituent a colloidal solution of coal tar pitch in solvent naphtha and which will readily dry to form a smooth glossy surface, the coal tar pitch having been derived from a tar containing not over six per cent. of free carhon. a

f. The method of making a colloidal solution of coal tar pitch in solvent naphtha which will readily dry to form a smooth glossy surface, consisting in melting solid with solvent naphtha at a temperature of be tween 100 degrees. and 200 degrees centi a e. {L l 5.. The method of making a colloidal 01 tion of coal ta r pitch in solvent naphtha, .ielri testimony whereof, I have hereunto set consisting of mixing melted pitch with $01 my hand. vent naphtha, at a tempenature of between 100 degrees and 200 degrees Centigrade, the HFREDERICK SPERR 5 solvent naphtha being added 2a propertien Witnesses :7

less than that which will produce precipita- GEO. B. BLEMING,

tion nf the piteh. W. C. LYON. 

